Parallel Scavenge: algorithm ParallelOldGC

Dang Nhan Nguyen nhann at
Tue Feb 5 10:00:21 UTC 2013

Hi Tao,

The Patent seems to cover the scavenge algorithm, not the parallel mark-compact algorithm that I asked.

From: hotspot-gc-dev-bounces at [hotspot-gc-dev-bounces at] on behalf of Tao Mao [tao.mao at]
Sent: Saturday, February 02, 2013 2:34 AM
Cc: hotspot-gc-dev at
Subject: Re: Parallel Scavenge: algorithm ParallelOldGC

Hi Nguyen,

The fundamentals should be covered by a then-Sun patent.


On 2/1/2013 3:51 PM, Jon Masamitsu wrote:
> Are you asking which hotspot source code is
> used when UseParallelOldGC is turned on?
> Or are you asking for a description of the
> algorithm?  Actually, the answer to both is
> share/vm/gc_implementation/parallelScavenge/psParallelCompact.*
> I'm not aware of any publications on the specific
> algorithm we used.  Comments in the header file
> are all I know about.
> Jon
> On 1/30/2013 6:43 AM, Dang Nhan Nguyen wrote:
>> Hi all,
>> I would like to ask about Parallel Scavenge GC:
>> Which parallel mark-compact algorithm is used for the old generation
>> in Parallel Scavenge GC (when XX:+UseParallelOldGC is set)?
>> (Reference to publication(s) are appreciated)
>> Thanks,
>> /Nhan Nguyen

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